1. Field of the Invention
The present invention relates to an electrostatic detection apparatus used in a touch panel and a glide point and, more particularly, relates to an electrostatic detection apparatus in which detection accuracy is improved by making it unsusceptible to influences from areas other than a sensing area.
2. Description of the Related Art
As a related art associated with an electrostatic detection apparatus according to the present invention, for example, a pad-type pointing device disclosed in, for example, U.S. Pat. No. 2003/0052867A1, is known.
In U.S. Pat. No. 2003/0052867A1, an X electrode layer 20X formed of a plurality of X electrodes x1, x2, . . . , x15, x16 that extend in the X direction and that are arranged at a predetermined spacing in the Y direction on the under surface of a film substrate 10 is provided. An insulating film 12 is formed on the surface (under surface) of the X electrode layer 20X. Furthermore, a Y electrode layer 20Y formed of a plurality of Y electrodes y1, y2, . . . , y15, y16 that extend in the Y direction and that are arranged at a predetermined spacing in the X direction on the surface (under surface) of the insulating film 12 is formed. That is, the X electrode layer 20X and the Y electrode layer 20Y are provided on the under surface of the film substrate 10 in such a manner as to be arranged to oppose each other in a matrix so as to intersect at right angles to each other via the insulating film 12.
The Y electrodes y1, y2, . . . , y15, y16 and the X electrodes x1, x2, . . . , x15, x16 extend via a through hole, a contact, electrodes, etc., provided in the edge portions of the insulating film 12. Finally, they are collected in an end portion Ds of an extension section 11 of the film substrate 10, and are connected therefrom to a conduction section 5 of a control substrate circuit 4.
The electrostatic detection apparatus detects the position of a body to be detected in the X and Y directions by detecting the change of an electrostatic capacitance formed between the body to be detected and each of the X electrodes and between the body to be detected and each of the Y electrodes when the body to be detected, such as a finger, is made to approach the X electrode layer and the Y electrode layer.
Therefore, in order to improve the detection accuracy in the X and Y directions, when the body to be detected approaches an electrode other than each of the X and Y electrodes, it is necessary that an electrostatic capacitance is not formed between those electrodes and the body to be detected, or it is necessary that, even if the electrostatic capacitance is formed, the amount of the change thereof is small.
However, in the electrostatic detection apparatus of the related art, the extension lines that extend from the end portions of the Y electrodes y1, y2, . . . , y15, y16 and the X electrodes x1, x2, . . . , x15, x16 and that extend up to a through hole are arranged so as to be adjacent to the Y electrodes and the X electrodes. Consequently, an electrostatic capacitance is easily formed between the extension lines and the body to be detected, and moreover, the amount of the change thereof cannot be decreased, presenting a problem in that it is difficult to improve the accuracy of position detection of the body to be detected in the X and Y directions.